A Novel Amplitude-Phase Tunable Coding Metasurface

This paper presents the design of a novel coding metasurface with independent control of amplitude and phase, aimed at manipulating electromagnetic (EM) wave beams. The unit cell of the coding metasurface consists of a square ring, a circular defect ring, and two tunable resistors. By adjusting the resistance values, modulation of the EM wave amplitude is achieved without altering the shape of the beam. The direction of the EM wave beam is determined by designing different coding patterns. Furthermore, by employing optimized coding, the reflected EM waves can be directed toward multiple directions, enabling radar cross section (RCS) reduction. Compared to an ideal metal conductor of the same size, the proposed metasurface achieves an RCS reduction that exceeds 10 dB in the frequency range of$6-19.2 \text{GHz}$, with a relative bandwidth of 108%. The simulation results verify the functionalities of the designed metasurface, providing an effective method for flexible manipulation of EM waves and RCS reduction.